GeoNames is a project to gather geographical information under the creative commons attribution license, which means it's ideal for commercial use and hobbyists alike.
The version I have contains a whopping 6.7 million. names of populated places, locations and all kinds of other things that have a name and ...
The more I use Sequel, the more I am coming to believe the level of abstraction it picks is just right. You use operations that mirror SQL, but in a mostly Ruby-ish way. Most importantly SQL is so completely wrapped that I've yet to see any need to write "raw" ...